Muscle of the Month: Latissimus Dorsi

Latissimus Dorsi

Location: The latissimus dorsi is one of the largest muscles in the back, located in the middle of the back and partially covered by the trapezius.

Attachments (where the muscle starts and ends):

Origin: Spinous processes T7-L5 vertebrae, Iliac Crest of Sacrum. Thoracolumbar Fascia, Inferior Angle of the scapula, Lower 3-4 ribs. Essentially, the muscles begins on the lower part of the spine, upper pelvis, and the lower ribs with an attachment to the scapula as well.

Insertion: Floor of intertubercular groove of the humerus, or the top of the upper arm.

Action(s):

Adduction of the arm at the shoulder

Extension of the arm at the shoulder

Internal rotation of the arm at the shoulder

Assists with flexion, extension, and lateral flexion of the trunk

Assists with anterior and lateral pelvic tilt

Assists with depression and protracton of scapula

Assists with deep inspiration and forced expiration

Exercises that use this muscle:

Pull-ups

Chin-ups

Lat Pulldown

Straight Arm Pulldown

Bent-over rows w/underhand grip

Seated Row

Swimming

Summary: Latissimus Dorsi Muscle literally means, “broadest muscle of the back”. With that being said, it is one of the widest muscles in the entire body. Although the lats are not used commonly in daily activities, they are generally active in the majority of pulling movements. If you are ever going rock climbing or like to climb ropes, be sure to train your lats!